1 files changed, 346 insertions, 0 deletions
diff --git a/kernel_call/platform_match.c b/kernel_call/platform_match.c
new file mode 100755
index 0000000..8226be5
--- /dev/null
+++ b/kernel_call/platform_match.c
@@ -0,0 +1,346 @@
+/*
+ * platform_match.c
+ * Brandon Azad
+ */
+#include "platform_match.h"
+
+#include <assert.h>
+#include <string.h>
+
+#include "log.h"
+#include "platform.h"
+
+// ---- Matching helper functions -----------------------------------------------------------------
+
+// Advance past any spaces in a string.
+static void
+skip_spaces(const char **p) {
+	const char *pch = *p;
+	while (*pch == ' ') {
+		pch++;
+	}
+	*p = pch;
+}
+
+// ---- Device matching ---------------------------------------------------------------------------
+
+// A wildcard device version number.
+#define ANY ((unsigned)(-1))
+
+// Parse the version part of a device string.
+static bool
+parse_device_version_internal(const char *device_version, unsigned *major, unsigned *minor,
+		bool allow_wildcard, const char **end) {
+	const char *p = device_version;
+	// Parse the major version, which might be a wildcard.
+	unsigned maj = 0;
+	if (allow_wildcard && *p == '*') {
+		maj = ANY;
+		p++;
+	} else {
+		for (;;) {
+			char ch = *p;
+			if (ch < '0' || '9' < ch) {
+				break;
+			}
+			maj = maj * 10 + (ch - '0');
+			p++;
+		}
+	}
+	// Make sure we got the comma.
+	if (*p != ',') {
+		return false;
+	}
+	p++;
+	// Parse the minor version, which might be a wildcard.
+	unsigned min = 0;
+	if (allow_wildcard && *p == '*') {
+		min = ANY;
+		p++;
+	} else {
+		for (;;) {
+			char ch = *p;
+			if (ch < '0' || '9' < ch) {
+				break;
+			}
+			min = min * 10 + (ch - '0');
+			p++;
+		}
+	}
+	// If end is NULL, then require that we're at the end of the string. Else, return the end
+	// of what we parsed.
+	if (end == NULL) {
+		if (*p != 0) {
+			return false;
+		}
+	} else {
+		*end = p;
+	}
+	// Return the values.
+	*major = maj;
+	*minor = min;
+	return true;
+}
+
+// Parse a device name.
+static bool
+parse_device_internal(const char *device, char *device_type, unsigned *major, unsigned *minor,
+		bool allow_wildcard, const char **end) {
+	// "iPhone11,8" -> "iPhone", 11, 8; "iPad7,*" -> "iPad", 7, ANY
+	// If this device name doesn't have a comma then we don't know how to parse it. Just set
+	// the whole thing as the device type.
+	const char *comma = strchr(device, ',');
+	if (comma == NULL) {
+unknown:
+		strcpy(device_type, device);
+		*major = 0;
+		*minor = 0;
+		return false;
+	}
+	// Walk backwards from the comma to the start of the major version.
+	if (comma == device) {
+		goto unknown;
+	}
+	const char *p = comma;
+	for (;;) {
+		char ch = *(p - 1);
+		if (!(('0' <= ch && ch <= '9') || (allow_wildcard && ch == '*'))) {
+			break;
+		}
+		p--;
+		if (p == device) {
+			goto unknown;
+		}
+	}
+	if (p == comma) {
+		goto unknown;
+	}
+	size_t device_type_length = p - device;
+	// Parse the version numbers.
+	bool ok = parse_device_version_internal(p, major, minor, allow_wildcard, end);
+	if (!ok) {
+		goto unknown;
+	}
+	// Return the device_type string. This is last in case it's shared with the device string.
+	strncpy(device_type, device, device_type_length);
+	device_type[device_type_length] = 0;
+	return true;
+}
+
+// Parse a device name.
+static bool
+parse_device(const char *device, char *device_type, unsigned *major, unsigned *minor) {
+	return parse_device_internal(device, device_type, major, minor, false, NULL);
+}
+
+// Parse a device range string.
+static bool
+parse_device_range(const char *device, char *device_type,
+		unsigned *min_major, unsigned *min_minor,
+		unsigned *max_major, unsigned *max_minor,
+		const char **end) {
+	char dev_type[32];
+	const char *next = device;
+	// First parse a full device.
+	bool ok = parse_device_internal(next, dev_type, min_major, min_minor, true, &next);
+	if (!ok) {
+unknown:
+		strcpy(device_type, device);
+		*min_major = 0;
+		*min_minor = 0;
+		*max_major = 0;
+		*max_minor = 0;
+		return false;
+	}
+	// Optionally parse a separator and more versions.
+	if (*next == 0) {
+		*max_major = *min_major;
+		*max_minor = *min_minor;
+	} else if (*next == '-') {
+		next++;
+		ok = parse_device_version_internal(next, max_major, max_minor, true, &next);
+		if (!ok) {
+			goto unknown;
+		}
+	}
+	*end = next;
+	// Return the device_type.
+	strcpy(device_type, dev_type);
+	return true;
+}
+
+// Check if the given device number is numerically within range.
+static bool
+numerical_device_match(unsigned major, unsigned minor,
+		unsigned min_major, unsigned min_minor, unsigned max_major, unsigned max_minor) {
+	if (major < min_major && min_major != ANY) {
+		return false;
+	}
+	if ((major == min_major || min_major == ANY)
+			&& minor < min_minor && min_minor != ANY) {
+		return false;
+	}
+	if (major > max_major && max_major != ANY) {
+		return false;
+	}
+	if ((major == max_major || max_major == ANY)
+			&& minor > max_minor && max_minor != ANY) {
+		return false;
+	}
+	return true;
+}
+
+// Match a specific device against a device match list.
+static bool
+match_device(const char *device, const char *devices) {
+	if (devices == NULL || strcmp(devices, "*") == 0) {
+		return true;
+	}
+	// Parse this device.
+	char device_type[32];
+	unsigned major, minor;
+	parse_device(device, device_type, &major, &minor);
+	// Parse the match list.
+	const char *next = devices;
+	while (*next != 0) {
+		// Parse the next device range.
+		char match_device_type[32];
+		unsigned min_major, min_minor, max_major, max_minor;
+		parse_device_range(next, match_device_type, &min_major, &min_minor,
+				&max_major, &max_minor, &next);
+		if (*next != 0) {
+			skip_spaces(&next);
+			assert(*next == '|');
+			next++;
+			skip_spaces(&next);
+			assert(*next != 0);
+		}
+		// Check if this is a match.
+		if (strcmp(device_type, match_device_type) == 0
+				&& numerical_device_match(major, minor,
+					min_major, min_minor, max_major, max_minor)) {
+			return true;
+		}
+	}
+	return false;
+}
+
+// ---- Build matching ----------------------------------------------------------------------------
+
+// Parse a build version string into a uint64_t. Maintains comparison order.
+static uint64_t
+parse_build_version(const char *build, const char **end) {
+	// 16A5288q -> [2 bytes][1 byte][3 bytes][1 byte]
+	const char *p = build;
+	// Parse out the major number.
+	uint64_t major = 0;
+	for (;;) {
+		char ch = *p;
+		if (ch < '0' || '9' < ch) {
+			break;
+		}
+		major = major * 10 + (ch - '0');
+		p++;
+	}
+	// Parse out the minor.
+	uint64_t minor = 0;
+	for (;;) {
+		char ch = *p;
+		if (ch < 'A' || 'Z' < ch) {
+			break;
+		}
+		minor = (minor << 8) + ch;
+		p++;
+	}
+	// Parse out the patch.
+	uint64_t patch = 0;
+	for (;;) {
+		char ch = *p;
+		if (ch < '0' || '9' < ch) {
+			break;
+		}
+		patch = patch * 10 + (ch - '0');
+		p++;
+	}
+	// Parse out the alpha.
+	uint64_t alpha = 0;
+	for (;;) {
+		char ch = *p;
+		if (ch < 'a' || 'z' < ch) {
+			break;
+		}
+		alpha = (alpha << 8) + ch;
+		p++;
+	}
+	// Construct the full build version.
+	if (end != NULL) {
+		*end = p;
+	}
+	return ((major << (8 * 5))
+			| (minor << (8 * 4))
+			| (patch << (8 * 1))
+			| (alpha << (8 * 0)));
+}
+
+// Parse a build version range string.
+static void
+parse_build_version_range(const char *builds, uint64_t *version_min, uint64_t *version_max) {
+	const char *next = builds;
+	uint64_t min, max;
+	// Parse the lower range.
+	if (*next == '*') {
+		min = 0;
+		next++;
+	} else {
+		min = parse_build_version(next, &next);
+	}
+	// Parse the upper range (if it exists).
+	if (*next == 0) {
+		assert(min != 0);
+		max = min;
+	} else {
+		skip_spaces(&next);
+		assert(*next == '-');
+		next++;
+		skip_spaces(&next);
+		if (*next == '*') {
+			max = (uint64_t)(-1);
+			next++;
+		} else {
+			max = parse_build_version(next, &next);
+		}
+		assert(*next == 0);
+	}
+	*version_min = min;
+	*version_max = max;
+}
+
+// Check if the given build version string matches the build range.
+static bool
+match_build(const char *build, const char *builds) {
+	if (builds == NULL || strcmp(builds, "*") == 0) {
+		return true;
+	}
+	uint64_t version = parse_build_version(build, NULL);
+	uint64_t version_min, version_max;
+	parse_build_version_range(builds, &version_min, &version_max);
+	return (version_min <= version && version <= version_max);
+}
+
+// ---- Public API --------------------------------------------------------------------------------
+
+bool
+platform_matches_device(const char *device_range) {
+	return match_device(platform.machine, device_range);
+}
+
+bool
+platform_matches_build(const char *build_range) {
+	return match_build(platform.osversion, build_range);
+}
+
+bool
+platform_matches(const char *device_range, const char *build_range) {
+	return platform_matches_device(device_range)
+		&& platform_matches_build(build_range);
+}